I've found the reason why I've been thinking this wrong way.
`getattr(self.get_queryset(), name)` is getting a bound method from
Manager.get_queryset() which is a QuerySet class instance, while method is
getting function from _queryset_class.
The difference is one of them is bound method, while the other is function.
在2024年2月28日星期三 UTC+8 10:13:09<Tim Graham> 写道：
> Hi Ryoma, a good way to investigate this would be to make the change and
> see if anything breaks.
>
> If I understand correctly, your suggest is:
>
> - return getattr(self.get_queryset(), name)(*args, **kwargs)
> + return method(*args, **kwargs)
>
> In that case, running the test suite gives this error:
>
> File "/home/tim/code/django/django/db/models/manager.py", line 89, in
> manager_method
> return method(*args, **kwargs)
> ^^^^^^^^^^^^^^^^^^^^^^^
> TypeError: QuerySet.using() missing 1 required positional argument: 'alias'
>
> I leave further investigation to you. :-)
> On Tuesday, February 27, 2024 at 7:28:05 PM UTC-5 Ryoma Han wrote:
>
>> I've been reading through the Django source code the last few days. When
>> I was reading the BaseManager source code I saw a method like this:
>>
>> ```python
>> @classmethod
>> def _get_queryset_methods(cls, queryset_class):
>> def create_method(name, method):
>> @wraps(method)
>> def manager_method(self, *args, **kwargs):
>> return getattr(self.get_queryset(), name)(*args, **kwargs)
>>
>> return manager_method
>>
>> new_methods = {}
>> for name, method in inspect.getmembers(
>> queryset_class, predicate=inspect.isfunction
>> ):
>> if hasattr(cls, name):
>> continue
>> queryset_only = getattr(method, "queryset_only", None)
>> if queryset_only or (queryset_only is None and
>> name.startswith("_")):
>> continue
>> new_methods[name] = create_method(name, method)
>> return new_methods
>> ```
>>
>> My question is why we use `getattr(self.get_queryset(), name)` insted of
>> just use `method`.
>>
>
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